I. Technical Field
The present invention relates to a unit for dissolving, with a liquid solvent, an adhesive member (such as adhesive and adhesive sheet) that sticks two bodies together.
II. Description of the Related Art
In recent years, techniques for thinning a wafer and peripheral techniques have been gathering attention. When a wafer is thinned, the strength of the surface is reduced and warping is generated over the entirety of the surface. Because of this, support is required using another support member when handling the wafer. Therefore, the surface strength of a wafer that is to be thinned is reinforced, for example, by pre-attaching a support plate made of glass, iron-nickel alloy or the like to the wafer, and thereby it is handled in such a way so as to cause no warping.
The above described support plate is adhesively attached to a wafer by using a member possessing adhesiveness between the support plate and the wafer. After the wafer is thinned, the support member is no longer required and therefore it is detached from the wafer. Specifically, the support plate is attached to the wafer using an adhesive member such as adhesive and therefore the wafer is detached from the support plate by making the adhesive member come into contact with a liquid solvent, e.g., alcohol (especially an alcohol with a small molecular weight such as ethanol or methanol), ketone, or a solvent produced by mixing alcohol with ketone and dissolving it.
The support plate is configured in various forms. Among these forms, a type produced by forming a large number of minute through holes in the thickness direction of the support plate (i.e., this type is called “support plate” in the present specification document) makes it possible to cause the above described solvent to come into contact, through the aforementioned through holes, with the adhesive member intervening between itself and the wafer. This configuration makes it possible to cause the majority of the above described adhesive member to react to the above described liquid solvent in a short time.
Note that the configuration of the support plate made of iron-nickel alloy and provided with the above described through holes is disclosed in reference patent document 1 and others.
When the support plate provided with through holes is used as a support member for a wafer as described above, the support plate is detached from the wafer by supplying the adhesive member with a liquid solvent through the large number of through holes. When the liquid solvent is accumulated in the through holes, the dissolution progresses successively from the adhesive member exposed to the opening part of the through hole toward the inside of the adhesive member.
[Patent document 1] Laid-Open Japanese Patent Application Publication No. 2005-191550
In the conventional apparatus, a liquid solvent remains in the above described through holes, hampering smooth circulation of the liquid solvent, and therefore a substantial length of time is actually required until the liquid solvent reacts with the better part of the adhesive member. The fact that the reaction time takes a substantial length of time is a problem because the reaction time directly affects the production efficiency.